1. Field of the Invention
The present invention generally relates to filtering noise effects out of digital signals using energy analysis of the digital coding. More particularly, this invention relates to a method for image stabilization for the output of analog-to-digital converters and for phase-locked loops.
2. Description of the Prior Art
Display images today often need stabilization and correction. Typically, this stabilization is required because of moving subjects or moving cameras. Without correction, the unstable images will be “fuzzy” or “blurred”. There are several techniques available in today's art. They include subdividing the image into nested pixel blocks in order to determine the overall image change in magnification, rotation, and translation. This determined change could then be used to correct the overall image. Another technique uses a sensor to detect the amount of movement of a display device and a correction circuit. Another technique uses displacement estimation and a feedback loop to achieve image alignment.
FIG. 1a shows an image display 11 with example pixels, x1, x2, x3, . . . , xn. In today's image processors, these individual pixels are normally processed using analog-to-digital converters (ADC) and phase-locked loops (PLL). Today's art typically does not address the image correction from the ADC and PLL circuit level.                U.S. Pat. No. 6,560,375 (Hathaway, et al.) describes a method of stabilizing and registering a video image in multiple video fields of a video sequence which provides accurate determination of the image change in magnification, rotation and translation between video fields, so that the video fields may be accurately corrected for these changes in the image in the video sequence. A key area of a video field is selected which contains an image which it is desired to stabilize in a video sequence. The area is subdivided into nested pixel blocks and the translation of each of the pixel blocks from the video field to a new video field is determined as a precursor to determining change in magnification, rotation and translation of the image from the key video field to the new video field.        U.S. Pat. No. 6,317,114 (Abali, et al.) discloses an image stabilizing apparatus and method for a display device having a display screen, include a sensor for sensing a movement of the display device, and a movement compensation circuit, coupled to the sensor, for compensating for the movement of the display device such that an image on the display screen of the display device remains stationary in relation to an observer's view.        U.S. Pat. No. 5,629,988 (Burt, et al.) describes a system and method for electronic stabilization of an image produced by an electronic imaging device. The input may be any sequence of image frames from an image source, such as a video camera, an IR or X-ray imager, radar, or from a storage medium such as computer disk memory, videotape or a computer graphics generator. The invention can also be used with images from multiple sources when these must be stabilized with respect to one another. The invention uses a feedback loop and second image warp stage to achieve precise image alignment as part of the displacement estimation process.        